The art of design and manufacturing ICs is generally known. Over the years, as the technology of designing and manufacturing ICs continues to improve, increasing number of electronic elements are being packed into a single IC, and the interrelationship between these elements are increasingly complex. With increased density and complexity, the cost for making an IC manufacturing mask has increased substantially correspondingly.
Between different offerings of a modern IC product family, or between successive offerings, often times the functionalities are different only in a relatively small incremental way, when viewed in the context of the totality of its logic. Thus, in view of the high cost of a new IC mask as well as other factors, increasingly IC designers desire to have ICs that are partially reconfigurable to accommodate the small incremental changes in functionalities between the different offerings.
U.S. Pat. No. 5,574,388 discloses a reconfigurable IC designed for emulation application. The architecture including in particular the integrated debugging facilities was particularly suitable for the intended use. However, general purpose partially reconfigurable integrated circuits present a different set of challenges. One desirable attribute is scalability to provide more flexible tradeoffs between area consumption versus routability.